Abstract

Measurements have been made in lanthanide nicotinate dihydrate (LnND) single crystals, where Ln = Dy and Er, of optical absorption, including the Zeeman effect, of magnetic susceptibility between 1.4 and 4.2 K, of electron paramagnetic resonance between about 9 and 35 GHz, and of magnetic resonance at 22 MHz. As in the case of TmND (Baker et al. 1986a), the measurements are consistent with a ground state with a large amplitude of M$_{J}$ = $\pm $J, an almost Ising-like g-matrix, and a purely magnetic dipole-dipole interaction between nearest-neighbour Ln$^{3+}$ ions. In this respect, the Kramers ions Dy$^{3+}$ and Er$^{3+}$ exhibit features similar to the non-Kramers ions Tb$^{3+}$ and Tm$^{3+}$ in the nicotinate dihydrates.